Pulmonary hypertension (PH), also known as pulmonary arterial hypertension (PAH), is a disorder characterized by high blood pressure in the arteries that supply the lungs. Pulmonary hypertension is often classified as either secondary pulmonary hypertension (SPH), in which the cause of the elevated blood pressure is known, or primary pulmonary hypertension (PPH), in which the cause is unknown. Examples of pre-existing conditions that may cause SPH include chronic obstructive pulmonary disease (COPD), sleep apnea, emphysema, bronchitis, sclerodema, CREST syndrome, systemic lupus erythematosus, chronic pulmonary thromboembolism, HIV infection, liver disease, and certain congenital heart diseases. Certain diet drugs such as fenfluramine and dexfenfluramine may also cause SPH.
In addition to high arterial blood pressure, PH may also be characterized by: narrowing and/or stiffening of the pulmonary arteries as the muscles within the walls of the arteries tighten or thicken; the formation of scar tissue in the walls of the pulmonary arteries; and the formation of blood clots within the smaller pulmonary arteries.
Symptoms of pulmonary hypertension include shortness of breath with minimal exertion, fatigue, chest pain, dizzy spells, low blood pressure, and fainting. The blood pressure in the pulmonary arteries of a patient suffering from PH may be twice as high or higher than the pulmonary blood pressure in a normal, healthy individual.
Although PPH is extremely rare, occurring in about two persons per million population per year, SPH is far more common and represents a significant medical concern for the population as a whole. Pulmonary hypertension is frequently misdiagnosed and progresses to late stage before it is accurately diagnosed.
There is no known cure for PH; current methods of treatment focus on prolonging patient lifespan and enhancing patient quality of life. Current methods of treatment of PH include administration of: vasodilators such as prostacyclin, epoprostenol, and sildenafil; endothelin receptor antagonists such as bosentan; calcium channel blockers such as amlodipine, diltiazem, and nifedipine; anticoagulants such as warfarin; and diuretics. Treatment of PH has also been carried out using oxygen therapy; and lung and/or heart transplantation. Each of these methods, however, suffers from one or multiple drawbacks which may include lack of effectiveness, serious side effects, low patient compliance, and high cost.
An ideal method of treatment would eliminate or significantly reduce the symptoms of PH, would lower pulmonary pressures, would be substantially more effective and easy to administer, and would have minimal or no side effects. The present disclosure is directed at providing one or more of these characteristics in a chemotherapeutic method for treating PH.